96 THE ECHINODERMATA. § 97. 



§ 9T. 



In the Crinoi'dea, these organs, in the form of tubes, are situated under 

 the soft perisoma of the pinnulae, and probably are without proper excre- 

 tory ducts. ^^ 



In the Ophiuridae, they consist of lobular, pedunculated sacs, which are 

 suspended in pairs in the inter-radial spaces of the disc. 



These ten organs are usually deeply fissured, and the lobules thus formed 

 appear as so many proper sacs attached to the peduncle.'-^ These last are 

 sometimes subdivided also.^''* 



Sometimes each organ, divided in its whole length into lobules, is turned 

 in the shape of a ram's horn.^^' The peduncle of these organs is directed 

 towards the mouth, but it -is yet uncertain whether their contents escape 

 this way or fall into the cavity of the body. In the first case, the pedun- 

 cle would be the excretory duct ;^'*' and in the second, the eggs and sperm 

 would escape through the respiratory openings.'"* 



In the Asteroidae these organs consist of varicose lobular sacs, situated 

 in the angles of the inter-radial spaces.'"' In those species which are without 

 an anus, there are no proper genital openings ; •'^^ these openings are also 

 wanting in those Asteroidae which have an anus.'^' In these last, the sperm 

 and very small eggs pass into the cavity of the body, and probably have 

 their escape through the respiratory openings.'^''' 



But in some species,™ there are upon the back and near each angle of 

 the inter-radial spaces two small approximated plates, perforated by small 

 openings [Laminae crihrosae). These are the simple openings of these 

 organs, which here consist of multi-ramose sacs, situated all along each side 

 of the inter-x'adial septa, to the common duct which opens through one of the 

 plates. 



The number of these genital sacs varies widely in the different genera 

 of the Asteroidae. In many, a single trunk of them hangs on each side of 

 the inter-radial septa ;f^' in others, there is a whole row of them ;<^^* and in 

 others still, there are two rows attached to the dorsal surface of the cavity 

 of the body, and extending into the rays.'"' 



In the Echinoi'dea, these organs descend along the internal surface of 



1 The development of the genital organs of 8 As in Astropecten and Luidia. 

 Comatula was first observed by Dujardin, who 9 As in Ophidiaster. 



asserts that the red vesicles situated on both sides 10 According to Sars, the ventral surface of the 



of the tentacular furrows secrete, during the epoch disc and arms of the female Echinaster sanguin- 



of rut, a very beautifully red liquid (L'lustit. No. olentus and Asteracanlhion Millleri have at cer- 



119, p. 268, or fFiegmann''s Arch. 1836, II. p. tain times a kind of incubating cavity, in which the 



207). Thompson has seen the eggs of Comatula eggs remain during their development. lie thinka 



escape in clusters through the openings of the pin- they get there from the cavity of the body, through 



nulae (Edinb. New Philos. Jour. No. XX. p. 295, particular openings upon the ventral surface of this 



or Froriep's neue Not. No. 1057, 1836, p. 4, fig. last ; see TFiegmann's Arch. 18i4, I. p. 169, Taf. 



8) ; while, according to Muller, they escape by VI. fig. 1, 2. * 



rupture (Abhandl. d. Berl. Akad. 1841, p. 234, Taf. The genital parts of Echinaster san^uinolentus 



V. fig. 17, 18). have been described with much detail by Sars, 



2 Ophioderma lon^icauda, and Ophiolepis Faun, littor. Norveg. p. 48. 



seolopendrica ; see Rathki, Foriep's neue Not. H Asteracanlhion rubens, and Solaster pap- 



No. 269, p. 6.5 ; and, Neueste Schrift. d. Natui-- posus ; see Miiller and Troschel, loo. cit. Taf. 



forsch. Gesellsch. m Danzig. HI. Hft. IV. 1842, p. XII. fig. 2-4. 



116, Taf. II. fig. 3, 4. 12 Echinaster, Astrogonium, Asteriscus, and 



3 Ophiocoma ni^ra; see Rathki, Danzig. Ctenodisctis. 



Schrift. &c. loc. cit. Taf. n. fig. 5-7. W Astropecten, Oreaster, and Culcita ; see 



4 Ophiothrix fragilis. Tiedemann, loc. cit. p. 61, Taf. VIII. L. L. 



5 Rathki, loc. cit. 14 Archaster, Chaetaster, Luidia and Ophidi- 

 •5 Miiller and Troschel, loc. cit p. 133. aster ; see Miiller and TroscheL loc. cit. Taf. 

 7 Miiller and Troschel have very interesting XII. fig. 5. 



details upon the various arrangements of the geni- 

 tal organs of the Asteroidae (loc. cit. p. 132). 



